Method for mounting work in a holder



March 1949- E. E. STEVENSON I METHOD FOR MQUNTING WORK IN HOLDERS Filed May 22, 1944 2 Sheets-Sheet 2- J F w W U H INVENTOR. f /wam/fsffeveuson Patented Mar. 1, 1949 METHOD FOR MOU HOL NTING WORK IN A DER Edward E. Stevenson, Whittier, Calif assignor to GlobeOil Tools Company, Los Nietos, Calif a corporation of California Application May 22, 1944, Serial No. 536,754

2 Claims. (01. 51---290) This invention has to do with a method for mounting work in a holder and it is a general object of the invention to provide a simple, eflective and commercially practical method for handling work that is difficult or impractical to handle with ordinary tools or equipment.

There are numerous situations where machine operations such as grinding or turning are required on parts or 'work difiicult to mount ac ourately and effectively. In mounting some work extremeaccuracy is required while in other cases the work may be delicate or it may be shaped so that it is extremely difiicult to "grip it effectively for holding during use or handling in a machine.

The usual methods and equipment for handling work, such as I refer to, involve chucks or special fixtures, all of which are subject to inaccuracy and are frequently ineffective and unsuited for certain classes of work. The usual work holding chucks involve a plurality of jaws thathold work with reasonable accuracy if the work presents true, finished parts to be engaged by the jaws,

but when the work is irregular or oddly shaped it is usually necessary that it be individually mounted andadjusted by a skillful operator with a resultant loss of time.

It is a general object of my present invention to provide a method for mounting a unit of work in a holder so that it is firmly and accurately held :in a predetermined position-inthe holder quite regardless-of irregularities or shape that would make it-difiicultand impractical to handle in the usual chuck, or the like. 'By my present invention I'mount the work in a'holderso thatit is accurately and firmly supported therein and the holder is such that it can be readily and accurately-mounted in a suitable machine such as a grinder or lathe.

It is another objectof my inventionto provide a method of mountingwork which can be carried out by ordinary workmen without the exerciseof great skillorcare and without the slow, tedious operations that characterize the :accurate mounting of work ina chuck, or the'like.

It is another object of my invention to provide ajmethod ofthecharacterabovereierred to which can be carriedout rapidly and in amanner making the method practical for quantity production operations.

The various objects :and features of my invention will be *fully understood from the following detailed description of a typical preferred manner of carrying out the+method -of"-my"'invention, throughoutwhich :description reierence is rmadeitb theaccompanying, drawings, in which:

Fig. 1 is a general View of a unit of apparatus used in carrying out the present invention showing'the general arrangement and relationship of parts, certain of theparts being shown in section. Fig. 2 is aside view of a typical unit of work that can be handled by the method of the present in-* vention, a part thereof being broken awayto show in-section. Fig. 3 is .a side viewof the work holder employed in carrying out the present invention, a part thereof being broken away to show in section. Fig. 4 is a sectionalview illus-. trating a step :in the method of the present inventionandshowing the apparatus used in carrying it out, the work being shown arranged in the holder and the holder being illustrated in the head which supports it during the filling operation. Fig. 5 is a view similar to Fig. 4 showing the work centered in the holder and the gfiller applied to secure the work in the holder. Fig. *6 is a sectional view of the unit formed by the work holder and the filler which mounts the work in the holder and Fig. 7 is a view illustrating a machine to which the unit of Fig. 6 may beapplied for the performance of operations on the work.

.By my present invention I mount work in a holder so that these parts, with the filler that mounts the work in the holder, form a unit which is firm or solid and suitable for mounting or handling "in a machine such, for example, as a grinder or lathe. Theparticular form or nature of the holder will, in practice, vary with the size, shape or character of the work to be held and with the machine or apparatusto which the holder is tobe applied or in which it is to be handled.

.In the particular form of the invention and for purpose of example only I have illustratedand will refer to the work W as a cutter, such for example as a roller cutter employed in an earth boring tool. Irefer to this particular work element as it presents a typical part that can be advantageously handled by the method of the invention.

The .work or cutter W, as shown in the drawings, involves a body ll] of tapered cylindrical; form with teeth .H on its exterior and with finished parts [2 of various sizes and shapes at its interior. It is typical of devices ofthe character referred to that the teeth II on the exterior thereof have cutting material welded thereon and the teeth are, themselves, arranged or located on the exterior of the body so that the element as a whole may be said to be irregular, and individual cutters vary one from the other. Because of "the irregularities it isimpractical, if not impossible, to make a'holding fixture or to employ it being preferred in order to expedite such grinding that certain of it be done by entering the grinding tool from one end of the cutter while the rest is done by entering the grinding tool from the other end of the cutter. If an attempt is made to thus grind a cutter such as is shown in Fig. 2 using the usual mounting fixtures or chucks, it requires double chucking or mounting of the work, that is, it requires mounting the cutter in the chuck so that one end is exposed to the grinding tool, then later mounting the cutter in'thechuck so that the other end is' exposed to the grinding tool. It has been found in practice that even with the exercise of great care and skill it is practically impossible to thus handle a cutter and gain accuracy of finish of the parts l2.

The holder H employed in carrying out my invention is a simple, unitary device preferably annular in form and proportioned so that its interior accommodates the cutter or work W while its exterior adapts it to a machine such as a grinder or lathe. The work holder as illustrated in Fig. 3 preferably involves an annular body l3 sufi'iciently large in diameter to fit around the work W with considerableclearance. The opening or bore l4 through the body |3 may be tapered, as I have shown in the drawings. An inwardly projecting flange I5 is provided at the inner or small end of the body, the inner side or face |6 of the flange being accurately finished to be normal to the longitudinal axis or central axis of the holder. The outer face or side ll of the flange l5 is also finished to be smooth andparallel with the face Hi. In the particular form of holder illustrated the bore or opening.

through the body is'un'der cut at l8 adjacent the flange If) to assure positive retention of the filler as will be hereinafter described. I

The exterior of the body 13 of the holder has projecting parts that I will term ribs |9.which extend around it circumferentially and which are spaced apart axially. The outer surfaces or tion and of minimum diameter atits ends, so

that itjwill readily enterthe equipment hereinafter described. .v

In accordance with the method of the present inventionI mount the cutter W on the holder H by means of a fillerF to establish a unit such as I have shownin Fig. 6, and-I then handle this unit in a machine such as I have shown in Fig. 7. The; general steps of the method involve center ing and supporting the holder H in-a predetermined position, as shown in Fig. 4, then firmly 4 holding the cutter W within the holder concentric thereto while the filler F is applied to fit between the holder and the work. It is believed that the various steps and details of the method will be best understood from a detailed description of the apparatus that I have provided and. from an explanation of just how that apparatus is used in handling the work W and the holder H.

' The apparatus employed in carrying out my present invention involves, generally, a head 25 toreceive and hold the holder H, means 26 for centering the work W in the holder, means 2? for applying a molten filler between the holder and work, and a head 28 for handling the unit formed by the holder H, work W and filler F.

The head provided for receiving and holding the holder H is a stationary or fixed part,

tubular in form and vertically disposed so that it opens upwardly. The upper end portion 30 of the bore or opening in the head 25 is finished and tapered to receive one of the finished flanges IQ of the holder H. In the particular case illustrated the opening or seat 30 in the head is tapered and accurately finished to receive the tapered finished'face 20 of the flange l9 located at'the end of the holder which has the flange l5. It should be observed that since the flanges l9 are alike and the tapered faces 20 are alike the holder can be arranged in the seat from either end or so either of the ribs thereof rest in the seat 3|].

The means 26 for centering the work W in the holder H while it is held in the head 25 includes upper and lower centers 3| and 32, respectively. The lower center 32 is an upwardly and inwardly tapered member on the upper end of a stem 33 carried in a guide 34. The guide 34 is fixed to the frame 35 of the apparatus and its upper end supports the head "25. In the particular case illustrated the head 25 is provided at its lower end with an inturned flange 36 which is screwthreaded onto the upper end of the guide 34. The stem 35 supports the center 32 so that it projects upwardly into the head 25. In the particular form of apparatus illustrated a compression spring 31 is arranged in the guide 34 below the lower end of the stem 33 so that the center 32 is yieldingly supported to project into the head.

The work'W is initially arranged in the holder H so that it is within the holder and in engagement with the center 32, but is slightly spaced above the inner side It of the flange provided on the inner or small end of the holder. This initial positioning of the work W in the holder H while the holder is centered and held in the head 25 is shown in Fig. 4 of the drawings.

The upper center 3| is located in alignment with the lower center 32'and is arranged above the lower center.. The upper center 3| is downwardly and inwardlytapered to enter the upper end of the work while it is in the holder H. The upper center may be formed or provided on the lower end of a stem 40 slidably mounted in a cylinder 4| supported by the flange 35 to be concentric with the guide 34. The stem 40 being slidably supported in th 'cylinder 4| can be moved down into engagement with the work while it is located in the holder supported in the head so that the two centers cooperate to firmly support and center the cutter or work within the holder with the end of the work seated on the flange l5 of the holder.

In, practice various means may be' provided for operating or reciprocating the stem 40 to obtain the desired action. In the particular case anemone A suitable control valve 5211s provided under control of anoperating member 53 so'thatfluid'can be admitted to and exhausted from theupper end of the cylinder, if desired. In the case illustrated I have provided a return spring 54 for moving the stem 40 .upwardly when fluid is exhausted from the upper endv of the cylinder 4 I.

With the mechanism just described when fluid from the supply line 5!] is admitted above the piston 5| the stem 40 is forced downwardlyso that it enters and engages the upper endof the work W and forces the work down in the holder against the resistance of the spring 31 until the bottom end of the work rests on the inner side A6 of the flange l5 of the holder.

In accordance with the method of my invention the work"W is set or made fast in the centered position vwithin the holder, as above described, by the application of a filler F between the interiorof the holder and the exterior of the work. This filler is applied or introduced into thespace between the holder and work in a molten state .and it is such as to solidify orbe solid at; normal temperatures. In practice I may employ various materials,

compositions or alloys as'the'filler F. I prefer to employer material which setsor solidifies into a solid, firm and strong body which is rigid and thus operates to set the work in the holder so it cannot shift. To avoid looseness I prefer to employ a material that does not shrink appreciably in cooling or in solidifying, as otherwise looseness might develop between the work and the holder.

In practice I have employed an alloy of bismuth, lead, cadmium and tin as the material for the filler, the particular composition used in practice having a melting point of about 180 F. which is less than the drawing temperature of work such as heat treated steel. Such alloy is melted easily and with the application of very little heat and yet is set or is in the solid form at normal temperatures at which it is desired to handle the work.

The means 21 for applying the molten filler between the holder and the work involves, generally, a heater A for the filler and a spout B for communicating the filler from the heater to the holder. The heater A may, in practice, vary Widely in form and construction. In the particular case illustrated I have shown the heater as a unit separate from the frame 35 of the apparatus and supported by a guide 60 so it can be bodily moved vertically by means of a screw 6| under control of an operating means 62.

The heater A, as illustrated, involves, generally, a melting pot 63, a burner 66 under the melting pot, and a control for supplying the molten filler from the pot 63 to the spout B.

The control, as illustrated, involves a riser 10 located at one side of the melting pot, a connection ll between the bottom of the melting pot and the bottom of the riser, a pivotal connection 12 between the inlet end of the spout B and a point at the side of the riser slightly above the normal level of filler in the pot 63, and a displacement member 14 for displacing the filler in the melting pot so it rises in the riser to fiow into the spout.

The displacement member I l may be located in the melting pot 63 and may be operated from ".n'ection .l2yas shown in Fig. 1.

a hand leverI-Bthrough a rod 16 a't the'exterior of the heater-which connects with a rod II that extendsdownwardly' into the melting pot to the member 113.

The pivotal connection 1'2 supports the spout 'B so thatit can be swung to any desired position. .Normally'the spout B is left so that it extends upwardly at a'slight angle from the pivotal con- The outer end or tip'llll of the spout is shaped to discharge into the holder H when the spout B is depressed or moved downwardly to a position wherethe filler material from the riser will flow through the spout.

In operating. the heater. and mechanism just described the burner-64 is operated to keep the material or filler in pot 63 in a molten state and heat from the burner also keeps the riser 'lfl hot so that filler herein stays in the molten state. A suitable jacket around the heated partsholds the heat so that the filler is readily maintained in the desired fluid state.

When it is desired to discharge filler from the heater Ato the holderI-I, while the holder is in the head 25 and' a unit of Work W is held and centered in the holder, the operator, if there'is sufiicient level of filler in the riser 18, may simply lower the spout B from a position such as is shown in Fig. 1 enough to allow filler 'to-runfrom ttheyriser'through the spout so it discharges into :theholder. In practice I have found it practical toihave 'the level of filler .in the riser normally below the point where the spout connects "to the riser. Flow of filler through'the spout is effected by operating lever IE to lower the displacement member M and thus increase the level of filler in the riser so the filler flows out through the spout.

When the desired amount of filler F has been poured into the holder H or when a substantial body of filler has been poured between the holder and the work the flow of filler is stopped by raising the spout B. The mass of metal presented by the holder and the work serves to rapidly chill the molten filler applied between the work and the holder so that it solidifies quickly. The moment the filler has solidified the means 26 may be released and the holder with the work set therein can be removed from the head 25.

The unit formed as just described and which is illustrated in Fig. 6 may then be placed in any suitable machine or unit of apparatus as circumstances require. In the case illustrated in the drawings I show in Fig. 7 a unit such as is shown in Fig. 6 applied to a mounting head 25 of a grinding machine. The grinding machine is shown in a general way as involving a spindle 91 which supports and rotates the head 25 so that the holder I-I mounted therein is rotated. A grinder spindle 92 projects from a support 93 and carries a grinding wheel 94. The spindle 92 may be fed into the opening in the work required to be finished.

When the surfaces accmsible from one end of the work unit have been finished the holder can be removed from the head 25 and reversed as to position or turned end for end, making the other end of the work accessible and convenient for the grinder. The details of the head 25 and the manner in which it cooperates with the holder H are more fully set forth and are the subject of my co-pending application entitled Device for handling work in a machine or the like, filed May 22, 1944, Serial No. 536,753. The apparatus disclosed herein is more particularly described and is claimed in my copending application entitled Apparatus for mounting work in a holder,

filed February 10, 1945, Serial No. 577,316.

Following the desired operations on the work W the holder with the work set therein is subjected to sufiic'ient heat to melt the filler F with the result that the filler flows from between the holder and the work leaving the work finished and leaving the holder available for reuse. By using a filler F such as I have referred to above, which melts at a fairly low temperature, ordinary metal parts can be handled without injuring them in any way, that is without drawing any temper or without discoloring them in any way. Further, by using an alloy such as I have referred to the filler melts away from the work, leaving it absolutely clean and in the same state that it was when inserted in the holder originally.

Having described only a typical manner of carrying out the method of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims.

Having described my invention, I claim:

1. The method of mounting a unit of work having a central opening in a tubular holder including, supporting the holder in avertical position closingv the lower end of the holder by locating the work unit to seat therein centralizing the work by introducing a center into the opening of the work unit at the holder, and then pouring a filler into the holder to solidify in the holder and around the exterior only of the work.

2. The method of mounting a unit of work having a central opening therethrough in a tubular holder including, holding the holder in a predetermined vertical position closing the lower end of the holder by seating the work unit there- .in, applying centering clamps to the ends of the opening in the work unit, then pouring a molten filler into the holder around the work clear of both ends of the work, and allowing the filler to solidify in the holder.

EDWARD E. STEVENSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

